Blade-mounting



H. F. SCHMIDT.

BLADE MOUNTING. APPLICATION FILED MAR. 3h (9H.

Patented Apr. 19, 192 1.

' ATTI'ORNEYS. I

r'r orlce.

HENRY F. SCHMIDT, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPORATION OF PENNSYLVANIA.

I BLADE-MOUN TING.

ars n.

T 0 all whom it may concern:

Be it known that I, HENRY F. SCHMIDT, a citizen of the United States, and a resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have made a new and useful Invention in Blade-Mounting, of which the following is a' specification.

Thisinvention relates to blade mountings and has for an object to produce a blade mounting Which will prevent bending stresses due to eccentric loading of the members of the mounting.

A- further object is to produce a blade mounting which is simpler lighter, more compact, and cheaper than other blade mountings now in use and lmown to me.

A further object is to produce a blade mounting which allows the weight of all the parts of a rotor wheel to bereduced.

A further object is to produce a blade mounting which is so constructed that wide flanges on the blade shank or blade carrying element are unnecessary.

These and other objects are attained by means of the blade mounting herein described, and illustrated in the drawings accompanying and forming apart hereof.

In the drawings: igure 1 is a sectional view of an embodiment of my invention. 7

Fig. 2 is a sectional view of another embodiment of my invention.

Fig. 3 is a sectional view of. a blade mounting in which a somewhat different device is employed in. accomplishing my invention.

One of the simplest forms of blade mounting is the familiar T-slot construction. A slot is cut in either the blade carrying element or the shank of the blade, and the other member is provided with a T-shaped tongue which fits snugly in the T-slot. A common construction is that in which the tongue is formed on the blade, or blade shank, and the T-slot inthe blade carrying element, as this member-inay be conveniently broadened or flanged soas to furnish material to allowthe slot to be formed without seriously weakening the structure. The pull of the blade due to the force of the steam acting on it, or to centrifugal force, or to a combination of both, tends to spread the groove and allow the T-shape'd tongue to slip out. This tendency is ordinarily resisted by the extra amount of metal allowed around the groove.

It is understood that the tongue is symmetrically loaded and is therefore only subjected Application filedMarchBl, 1917. Serial No. 158,978.

Specification of Letters Patent. Patented Apr. 19, 1921.

to pure tension stresses, while the material in which the groove is formed is eccentrically loaded and is subjected to heavy bending stresses.

My invention consists in providing means for counteracting the tendency of the groove to open out, or spread, due to eccentric loading, and to therefore eliminate substantially all bending strains. The resulting joint is as strong or stronger than joints built after the old construction, and is considerably lighter and more compact. Thesefeatures are of especial value where weight and space are both of unusual importance. The novel construction whereby I prevent bending strains due to eccentric loading is quite simple and is as easy to form as the old construction, hence my invention has the advantages ofreduced weight and space as well as the simplicity, strength and cheapness of the old construction.

3 One of the greatest advantagesof my invention is that the elimination of the heavy blade mounting rim makes possiblea much lighter rotor wheel throughout. Such a rim, at the high speeds commonly employed, is not capable of fully resisting the stresses due to centrifugal force without the reinforcing and supporting effect of the body and hub of the" rotor wheel. 7 Consequently the entire wheel must be made heavy to properly resist the stresses occasioned by the heavy rim. 7 By means of my invention the heavy rim is eliminated and consequently the weight of the rest of the wheel may be reduced. If desirable the-hub portion may be dispensed with in built up rotors as it'is 'no'longer needed as a reinforcing element of the wheel.

In Fig. l I have illustrated a blade 16 mounted on a blade carrying member 17 by means of a T-sh'aped tongue 18, which fits'in tends to spread apart the material in which the groove is out. In order to counteract the tendency of the blade carrying element 17 to "s read I em 10 'two sets of compound P P Y Wedges. 19 and 20 for transmitting any stresses due to eccentric loading of the blade carrying element 17 to the shank of the blade 16. As the'wedges l9 and 20 are inserted at an angle they effectually clamp together the outer ends of the blade carrying element 17.

In Fig. 2, I have shown a construction similar to that shown in Fig. 1, except that the tongue and groove joint is reversed. A tongue 21 is carried by a blade carrying element-22 and compound wedges 23 and 2a are adapted to reinforce the shank of a blade 25, as before;

In Fig. 8, I have shown a blade mounting, which is a modification of that shown in Fig. 2. As before, a T-shaped tongue 26 carried by a blade carrying element 27is adapted to hold in place a blade 28, and compound wedges 29 and30, inserted between the blade carrying element 27 and the shank of the blade 28, are adapted to laterally tie the shank of the blade 28 together.

The advantages gained in weight and spacesaved through my invention are obvious from the constructions illustrated rendering the invention of particular importance to marine work or in other work where space and weight are of special importance. Furthermore, these advantages are gained with substantially no increase in first cost, with no sacrifice of strength, and with practically the same simplicity of construction.

While I have illustrated and described severalmodifioations' of my invention, it 3.5

will be apparent to those'skilled in the art, that various changes, modifications, additions and omissions may be made in the ap paratus illustrated without departing from the spirit and scope of the invention, as set forth by the appended claims.

What I claim is:

1. In combination, a blade element, a blade mounting element, a T-shaped tongue formed on one of said elements, an undercut groove formed in the other element and adapted to engage the tongue, wedge bearing surfaces onthe tongue bearing element extending on each side from and obliquely to the shank of the tongue, opposed wedge bearing surfaces on said grooved element extending from each side of and obliquely to the groove, said wedge bearing surfaces lying in planes diverging toward the center of said elements and wedges disposed between said bearing surfaces adapted to hold said elements against relative lateral displacement. I 1 2.. In combination, a blade element, a blade mounting element, an undercut groove formed in one of said elements, a tongue formed on the other element adapted to engage said groove, wedge bearing surfaces formed on the tongue carrying element on opposite sides of the tongue, opposed wedge bearing surfaces formed on the grooved ele opposed shoulder spaced from the shoulder of the grooved member so as to form an undercut channel between the shoulders obliquely disposed with respect torthe engaging surfaces of the tongue and tongue groove, of a wedge disposed between said shoulders and adapted to hold the members against relative lateral displacement.

4:. In combination with a blade element, a

blade mounting element, a tongue on one' of said elements, a groove in the other element and adapted to engage said tongue, a shoulder formed on the grooved element spaced from the tongue carrying element so as to form a channel between the said shoulder and said tongue carrying element, the inner portion of the channel being of greater width than the outer portion thereof and a wedge disposed in the said groove adapted to hold the said elements against relative lateral displacement.

5. In combination with a blade element, a blade mounting element, a tongue on one of said elements, a groove in theother'element adapted to engage said tongue, opposed wedge seats formed on the said elements and extending in planes oblique to the engaging surfaces of the tongue and tongue groove, and wedges bearing between said inclined wedge seats adapted to hold said elements against relative lateral displacement.

6. In combination, a blade element, a blade mounting element, an undercut groove formed in one of said elements, a tongue formed on the other element adapted to engage said groove, inclined wedge seats formed on opposite sides of each of'said elements and cooperating to form between the said inclined wedge seats channels of greater width at their inner portions than at their outer portions, said wedge seats extending in planes oblique to the engaging surfaces of the tongue and tongue groove, and wedges bearing against the inclined wedge seats and adapted to hold the said elements against relative lateral displacement.

7. In combination with a rotary blade mounting element and a blade element having tongue and groove engagement, wedge seats formed on the opposed ends of the elements extending in planes inclined outwardly from the plane of rotation lying centrally of these elements, the wedge seats cooperating to form channels of greater width at their inner portions than at their outer portions, wedges disposed in the channels adapted to hold the said elements against relative lateral displacement and adapted to be tightened by the rotational movement of the elements. 7

8. In combination, a blade element, a blade mounting element, the end of one of the elements being formed with a-centrally protruding T- shaped tongue and having wedge bearing surfaces extending outwardly from and forming an angle with the shank of the tongue, the end of the other element being formed with a cooperating T-shaped groove engaging the tongue and having wedge bearing surfaces extending outwardly from and forming an angle with the longitudinally extending engaging surfaces of the groove, said wedge bearing surfaces cooperating to form between them channels of greater width atthe inner than at the outer portions thereof, and wedges disposed in said channels to hold the members against relative lateral displacement and adapted to be tightened by the centrifugal forceoccasioned by rotary motion of the elements.

In testimony whereof, I have hereunto subscribed my name this 30th day of March, 191

HENRY F. SCHMIDT.

Witnesses:

C. W. MCGHEE, M. B. GORDON. 

